In the past, if you wanted to read up on best practices, I would have recommended the following:
- Web Performance Best Practices and Rules
- Behavioral Separation
It seems little has changed. You still choose your best practices based on the framework you are using. These frameworks, however, have moved from low-level (e.g. Dojo, jQuery) to high-level (e.g. React, Angular).
Some things do change. Certain best practices, like separate stylesheets, are being revisited. Others, like checking code style, are become more popular.